The Business of Technology




Project Management and Design of a Space Cryostat


In recent years, Oxford Instruments have been developing for the European Space Agency (ESA) a device for precision measurement of the force of gravity. The device, a Superconducting Gravity Gradiometer (SGG) operates at liquid helium temperature. The intention is that this device will map the gravity field of the earth with a degree of spatial accuracy and measurement precision far exceeding current data. This information is of importance to studies of ocean circulation currents (modified by global warming), vulcanology, and mineral prospecting.

The cryostat design is particularly critical: although cryostats for space use are well known, the SGG application gives particular difficulties. The most significant of these is that the closest mass to the SGG is the liquid helium. As the helium is consumed during the mission, the remaining helium in the vessel moves in an unpredictable and physically unstable way in the micro-gravity environment of space. This gravity noise signal destroys the utility of the instrument.

Work programme

Technology Enterprise took technical and management responsibility for the cryogenic aspects of the project, working with the Oxford Instruments team, with Mullard Space Science Labs (MSSL), Alenia Spazio and the University of Trenta.

Technology Enterprise was also engaged to co-ordinate and write the final report to Alenia Spazio and ESA for the whole work package. This involved coordinating input from several sites within the Oxford Instruments group and Mullard Space Science Labs (MSSL). It also involved understanding and summarising the results of several highly mathematical interim or internal technical reports for incorporation into the final document. The final document served two purposes: first, it provided a succinct technical summary of the work programme; second it provided a credible marketing document for subsequent contracts between ESA and Oxford Instruments.

This highly successful assignment was carried out on schedule and to cost.